The present invention relates to a subcutaneous-intramammary prosthesis and, in particular, to a mammary prosthesis designed to replace an annular section or quadrant of breast tissue after its resection for any pathological reason, such as, for example, partial mastectomy.
The mammary or breast prostheses which have been used in the past include external, brassiere-type prostheses which are believed to have been used when the breast has been amputated, and internal or subcutaneous prostheses. Subcutaneous mammary prostheses are used for breast augmentation, that is, to enhance the existing contour of healthy breast tissue, or for reconstruction, to restore and/or enhance the breast contour when abnormal, diseased or damaged tissue has been removed by surgery.
The breast augmentation prostheses which are known to me are typified by the silicone gel-filled, pad shaped flexible container which is disclosed in Rathjen, U.S. Pat. No. 3,902,198, issued Sept. 2, 1975. Rathjen also discloses the use of porous fixation loops, which are attached to the posterior wall of the pad, and are invaded by body tissue to fix or anchor the prosthesis to the chest wall. In addition, Rathjen suggests the optional use of absorbable sutures to temporarily hold the implant in place until the anchoring or fixation is complete.
The only subcutaneous reconstructive prostheses which are known to me are those which are used to totally reconstruct or replace the breast after radical mastectomies. As is well-known to those who are familiar with breast surgery and the technology of the devices used in reconstructive surgery, reconstructive prostheses must possess the characteristics of softness and resiliency. At the same time, reconstructive prostheses must have sufficient rigidity for shape retention. In addition, it is desirable to provide fixation so that the device will retain its position without shifting during normal body movement.
Cronin, U.S. Pat. No. 3,293,663, issued Dec. 27, 1966, apparently typifies the silicone gel-filled, shaped, flexible containers which provide a soft, resilient, reconstructive human breast replacement. However, various attempts have been made to improve upon the shape retention capabilities of the basic gel-filled, flexible mammary prosthesis. For example, one approach for enhancing shape retention involves dividing the prosthesis internally into separate compartments. See Pangman, U.S. Pat. No. 3,559,214, issued Feb. 2, 1971. Also, Hamas, U.S. Pat. No. 4,264,990, issued May 5, 1981, uses a rigidizable backing structure which is attached to the posterior of the prosthesis to alleviate deformation caused by scar tissue contracture. Redinger, U.S. Pat. No. 4,455,691, issued June 26, 1984, uses a composite silicone elastomer container to decrease the outmigration of silicone gel.
In addition to the attempts to provide softness and resiliency in conjunction with shape retention, the art evidences attempts to fix reconstructive prostheses by attaching a porous fabric to the posterior of the prosthesis so that invasion by body tissue anchors the prosthesis to the chest wall. This approach is described in the Cronin patent. In addition, the Pangman patent discloses the use of an outer foam covering which completely surrounds the prosthesis. The covering allows the in-growth of tissue to anchor the prosthesis, and, because of the covering's small thickness, limits the in-growth of the tissue and presumably reduces shrinkage and hardening due to encapsulation by scar tissue.